Volcanic stone sentinels stand watch at a Korean Bell Garden in Virginia.

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

Built by the patriotic residents of Boonsboro in a single day.

The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

The whole world in one water tank.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

Walk a trail through a historic Quaker town that outlawed slavery in 1777 and was a major waypoint on the Underground Railroad.

Ancient snack bar of the Roman Empire re-opened.

Erotic art covers the walls of the largest ancient pleasure palace.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

2300-year-old Roman road connecting the empire.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.